We are currently running Exchange 2000 sp3 with OWA using SSL and Clear Text or Integrated Windows Authentication. We had to enable Integrated Windows Authentication for the Mobile Information Server we have. Over the last week users running XP have not been able to login to OWA using IE with their domain\username. Windows 2000 and other browsers run fine. I also noticed that if I turn off Integrated Windows Authentication in the users Internet Explorer options, everything goes back to normal. My question is, has anyone else noticed a change in OWA and Windows XP and how can I modify my OWA security settings so that I don't have to instruct everyone using Windows XP and IE on how to adjust their internet settings?